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A Listeria monocytogenes mutant defective in bacteriophage attachment is attenuated in orally inoculated mice and impaired in enterocyte intracellular growth.

ABSTRACT: A Listeria monocytogenes bacteriophage was used to identify a phage-resistant Tn917 insertion mutant of the mouse-virulent listerial strain F6214-1. The mutant was attenuated when it was inoculated orally into female A/J mice and failed to replicate efficiently in cultured mouse enterocytes. Phage binding studies indicated that the mutant had a cell surface alteration that precluded phage attachment. All phenotypes associated with the mutation could be complemented in trans by a single open reading frame (ORF) that corresponded to the ORF interrupted by the Tn917 insertion. The complementation effected was, in all cases, at a level indistinguishable from that of the parent. The Tn917 insertion interrupted a gene that is predicted to encode a group 2 glycosyl transferase (provisionally designated glcV). A similar glcV gene is present in Listeria welshimeri and Listeria innocua and in some serotypes of L. monocytogenes. We speculate that the loss of the glcV product results in a defective phage receptor and that this alteration coincidentally influences a feature of the normal host-pathogen interaction required for virulence. Interestingly, the glcV lesion, while preventing phage attachment, did not alter the mutant's ability to bind to cultured mouse enterocyte monolayers. Rather, the mutation appeared to alter a subsequent step in intracellular replication measured by a reduction in plaque-forming efficiency and plaque size. In vivo, the mutant was undetectable in the liver and spleen 48 h after oral inoculation. The mutation is significant in part because it is one of the few that produce attenuation when the mutant is delivered orally.

SUBMITTER: Spears PA

PROVIDER: S-EPMC2519439 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature

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A Listeria monocytogenes mutant defective in bacteriophage attachment is attenuated in orally inoculated mice and impaired in enterocyte intracellular growth.

Spears Patricia A PA Suyemoto M Mitsu MM Palermo Angela M AM Horton John R JR Hamrick Terri S TS Havell Edward A EA Orndorff Paul E PE

Infection and immunity 20080616 9

A Listeria monocytogenes bacteriophage was used to identify a phage-resistant Tn917 insertion mutant of the mouse-virulent listerial strain F6214-1. The mutant was attenuated when it was inoculated orally into female A/J mice and failed to replicate efficiently in cultured mouse enterocytes. Phage binding studies indicated that the mutant had a cell surface alteration that precluded phage attachment. All phenotypes associated with the mutation could be complemented in trans by a single open read ...[more]

PMID: 18559424

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Project description:The Gram-positive pathogen Listeria monocytogenes can be subdivided into at least 12 different serovars, based on the differential expression of a set of somatic and flagellar antigens. Of note, strains belonging to serovars 1/2a, 1/2b, and 4b cause the vast majority of foodborne listeriosis cases and outbreaks. The standard protocol for serovar determination involves an agglutination method using a set of sera containing cell surface-recognizing antibodies. However, this procedure is imperfect in both precision and practicality, due to discrepancies resulting from subjective interpretation. Furthermore, the exact antigenic epitopes remain unclear, due to the preparation of the absorbed sera and the complex nature of polyvalent antibody binding. Here, we present a novel method for quantitative somatic antigen differentiation using a set of recombinant affinity proteins (cell wall-binding domains and receptor-binding proteins) derived from a collection of Listeria bacteriophages. These proteins enable rapid, objective, and precise identification of the different teichoic acid glycopolymer structures, which represent the O-antigens, and allow a near-complete differentiation. This glycotyping approach confirmed serovar designations of over 60 previously characterized Listeria strains. Using select phage receptor-binding proteins coupled to paramagnetic beads, we also demonstrate the ability to specifically isolate serovar 1/2 or 4b cells from a mixed culture. In addition, glycotyping led to the discovery that strains designated serovar 4e actually possess an intermediate 4b-4d teichoic acid glycosylation pattern, underpinning the high discerning power and precision of this novel technique.IMPORTANCEListeria monocytogenes is a ubiquitous opportunistic pathogen that presents a major concern to the food industry due to its propensity to cause foodborne illness. The Listeria genus contains 15 different serovars, with most of the variance depending on the wall-associated teichoic acid glycopolymers, which confer somatic antigenicity. Strains belonging to serovars 1/2 and 4b cause the vast majority of listeriosis cases and outbreaks, meaning that regulators, as well as the food industry itself, have an interest in rapidly identifying isolates of these particular serovars in food processing environments. Current methods for phenotypic serovar differentiation are slow and lack accuracy, and the food industry could benefit from new technologies allowing serovar-specific isolation. Therefore, the novel method described here for rapid glycotype determination could present a valuable asset to detect and control this bacterium.

Dataset Information

A Listeria monocytogenes mutant defective in bacteriophage attachment is attenuated in orally inoculated mice and impaired in enterocyte intracellular growth.

Publications

A Listeria monocytogenes mutant defective in bacteriophage attachment is attenuated in orally inoculated mice and impaired in enterocyte intracellular growth.

Similar Datasets

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